Obesity rates are low among elementary school students in Japan, as are adults, in contrast to the rising proportion of the overweight population in many countries. Eating habits are an important factor affecting obesity. Let us observe the nutritious lunch of Japanese elementary school students. Common foods: black beans, wheat, steamed vegetable rolls, mashed potatoes, pumpkin, boiled corn, citrus juice bibimbap, etc. Most of them are rich in meals fiber. Dietary fiber is not easily digested in the intestines, delays the emptying of the stomach, and reduces the growth rate of bad bacteria in the intestines.

Similar function to dietary fiber, it keeps the gut healthy and can also be obtained from starch-rich foods. This type of starch, which is not digestible but can be fermented by bacteria in the gut, that can promote intestinal peristalsis and defecation, is called Resistant Starch (RS).

Resistant starch is a granular modified starch, which is very common in daily food. For example, the black beans mentioned above are bean resistant starch; some root crops such as potatoes and green bananas too; in addition, we let the rice cool or sushi also has resistant starch, but these are not easy to store, or because the calorie density becomes lower, people who cannot control their appetite , sometimes they will eat more food in disguise, so the resistant starch made with modified starch is used. Resistant starch can avoid the above problems, and can also achieve the characteristics of high purity and stable product.